Information storage devices are used to retrieve and/or store data in computers and other consumer electronics devices. A magnetic hard disk drive is an example of an information storage device that includes one or more heads that can both read and write, but other information storage devices also include heads—sometimes including heads that cannot write.
In a modern magnetic hard disk drive device, each head is a sub-component of a head gimbal assembly (HGA) that typically includes a suspension assembly with a flexure to carry the electrical signals to and from the head. The HGA, in turn, is a sub-component of a head stack assembly (HSA) that typically includes a plurality of HGAs, an actuator, and a laminar flexible cable. The plurality of HGAs are attached to various arms of the actuator, and each of the flexures of the HGAs has a flexure tail that is electrically connected to a distal region of the HSA's laminar flexible cable.
Flexible cables in modern disk drives typically include conductive traces on a dielectric and flexible structural layer. The distal region of the laminar flexible cable is attached to, and moves with, the actuator, while a proximal region of the laminar flexible cable is fixed to the disk drive base by a connector bracket. The flexible cable may be reinforced by a stiffener (e.g. aluminum stiffener) in the distal region where the flexible cable is attached to the actuator body, to provide more structural rigidity to the flexible cable in the distal region. An integrated circuit (IC) chip (e.g. preamplifier chip) is typically also mounted on the flexible cable in the distal region.
The maximum width of flexible cables in modern disk drives is typically limited, for example by the height of the disk drive into which the flexible cable will be assembled. However, the size of modern disk drives has trended smaller, and there is no indication that such trend will reverse. Moreover, the number of required conductive traces on the flexible cable is generally increasing, since the number of conductive paths to each HGA has increased to enable additional structures in and functions of the modern HGA. For example, modern HGAs typically include both a read and write transducer, and may also include a microactuator, a heater, a touch-down detector, and/or a laser device to locally heat an adjacent disk medium. Hence, there is a need in the information storage device art for improved designs and methods to manufacture disk drive flexible cables that can accommodate a greater number of electrical traces with connections to a mounted IC chip (especially in the distal region of the flexible cable).